Many electrically actuated valves are subjected to rather harsh operating environments. Valves that are used in automotive vehicles are in this category and those that are mounted on, or in proximity to, a vehicle's engine are apt to experience perhaps the harshest environment. One such valve is an electric exhaust gas recirculation (EEGR) valve of the type used in exhaust emission control of internal combustion engines.
Exhaust gas recirculation is a technique that is used to reduce the oxides of nitrogen content of internal combustion engine exhaust gases. An EGR valve controls the amount of exhaust gas that is allowed to recirculate and mix with a fresh air-fuel induction stream that enters combustion chamber space of an engine, and is typically mounted directly on the engine. One type of electric actuator for such a valve is a solenoid actuator. The solenoid assembly comprises a bobbin-mounted electromagnet coil that is electrically connected to terminals of an electrical connector plug via which the valve electrically connects to an electrical control system for the engine.
In a valve that has an end closure cap that is assembled to an otherwise open axial end of a cylindrical shell that houses the electric actuator portion of the valve, magnet wire ends can be directly attached to bobbin-mounted terminals which in turn mate with terminals mounted in such an end closure cap. Ends of the closure-mounted terminals that are opposite the ends mated with the bobbin-mounted terminals are surrounded by a shell integrally formed in the end closure cap to create the electric connector plug via which the valve connects to the engine electrical control system. Such a construction provides assembly convenience and efficiency since the mating of the closure cap terminals to the bobbin terminals occurs as the closure cap is being assembled to the shell.
The present invention relates to a novel construction for maintaining the assembled axial integrity of such a valve, including a special metal clinch ring and a conventional O-ring seal where the end closure cap is assembled to the shell. Also a wave spring washer is placed in cooperative association between the bobbin and associated magnetic circuit structure to assure maintenance of axial location of the bobbin relative to such magnetic circuit structure. Thus, the invention combines assembly convenience with maintenance of assembled axial integrity so that valve operating performance does not degrade in harsh operating environments due to inability of the valve to maintain important axial relationships that are imparted to the valve at the time of its manufacture.
The foregoing, along with further advantages, features, and benefits of the invention, and the inventive principles are disclosed in the ensuing description of details of a specific embodiment that represents the best mode contemplated at this time for carrying out the invention. The drawings that accompany the disclosure depict in particular detail a presently preferred exemplary embodiment of the invention.